S
  • Saturation
    How rich the colors are in a photo.

  • Saturation levels
    Light intensity that exceeds the maximum level designed for a CCD.

  • scan head
    The part of the scanner containing fluorescent lamps that passes across an image.

  • Scanner
    A device that captures an image for your computer and converts it to a digital form that your computer can display, edit store and output. A scanner can be used for a wide variety of application, such as incorporating artwork or photos into documents, scanning printed text into your word processor to eliminate retyping, scanning faxed document into a database for storage, and adding images to multimedia productions.

  • Scanner Threshold
    Setting that determines whether a pixel is white or black.

  • Screen angle
    The angle at which the halftone screens are placed in relation to one another.

  • screen frequency
    See lpi.

  • Screen resolution
    The size of the rectangular grid of pixels displayed on a monitor.

  • Screen ruling
    Number of raster points either per inch or per centimetre. Measured in lines per cm (l/cm) or lines per inch (lpi). A 60 l/cm raster therefore corresponds with 152 lpi.

  • Screening
    Another name for halftoning.

  • SCSI
    An acronym for Small Computer System Interface. An industry standard interface that provides high-speed access to peripheral devices.

  • SCSI chain
    A group of SCSI devices linked to each other through SCSI peripheral interface cables and linked to the SCSI port on the computer through a SCSI system cable.

  • SCSI ID number
    A number assigned to each SCSI device connected to a computer. The Macintosh itself is assigned ID 7. Other devices may use IDs 6 through 0, with 6 indicating the highest priority for communications and 0 the lowest priority.

  • SCSI port
    A port that's faster than the serial and parallel ports but slower and harder to configure than the newer USB port. Also know as the Small Computer System Interface.

  • Sensitivity
    See ISO speed.

  • Serial
    A method for connecting an external device such as a printer, scanner, or camera, to a computer. It has been all but replaced by USB and FireWire in modern computers.

  • service bureau
    A business that specialises in printing computer files on an imagesetter.

  • Shade
    The brightness or luminance of an image when compared to a gray scale.

  • Shadow
    A term that refers to the amount of detail contained in the dark parts of an image. It is desirable to maintain shadow detail but there is a risk of decreasing overall contrast if one lightens the shadow too much in an attempt to expose detail. If an image is scanned without shadow detail, it will be impossible to regain detail in an image editing program.

  • Shadow Point
    The darkest tone printable in an image without being black. All tonal values below this threshold will print as black.

  • shadows
    The black and nearly black tones in an image.

  • Sharpen (Sharpening)
    Electronic photo-retouching function for enhancing image detail and contrast either globally or in selected regions of the picture.

  • Sharpen edges
    An image editor technique to enhance the edge of an object.

  • Sharpness
    An image degree of clarity in terms of focus and contrast.

  • Sheet film
    Film that is cut into individual flat piece. Used in large format view camera, with sizes like 4x5, 8x10 and 11x14 inches. Also called cut film.

  • Shelf life
    Is the length of time unused material or chemicals will remain fresh.

  • Shift
    "Movement on large format camera (or special "shift lens" in other formats) which can eliminate converging angles."

  • Shooting distance
    Refers to the distance between the subject and the film plane.

  • Shooting Modes
    The amount of control you have in choosing how your digital camera captures an image. All digital cameras usually have an Auto mode: the camera decides for you the best shutter speed/aperture settings.

  • Short lens
    Term describing a wide-angle lens (a lens whose focal length is shorter than the diagonal measurement of the film used).

  • Shutter release
    The mechanical or electromechanical button that releases the shutter and takes the exposure.

  • Shutter speeds
    The duration that the shutter is held open during an exposure. A typical range is from 1 full second to 1/1000 of a second. Combined with the lens aperture it controls the total amount of exposure.

  • Signal-to-noise ratio
    The ratio of the usable signal to unusable noise in a scan. A high degree of noise can mask the shadow detail in an image regardless of tonal resolution.

  • SLR
    Standing for single-lens reflex, these are higher-end digital cameras revered by serious photographers. The digital versions of SLRs work in this manner: the shutter retracts so an image can be recorded. One of the prime benefits of using a digital SLR camera is that lenses are interchangeable.

  • SmartMedia
    A wafer-thin, matchbook size memory card. This is also a flash-memory based storage medium.

  • Spectral data
    Colour information stored as multiple measurements (typically 16 32, or more ) across the range of wavelengths of visible light.

  • Spectrophotometer
    A device that captures colours as spectral data, thereby providing maximum accuracy in measuring and specifying colours.

  • Specular highlight
    A bright reflection from a light source containing little or no detail. Specular highlight within an image should not be used for Set Whitepoint.

  • Specular reflection
    "Light rays that are highly redirected at or near the same angle of incidence to a surface. Observation at this angle allows the viewer to "see" the light source."

  • Speed
    A measure of the sensitivity to light of a photographic emulsion.

  • Spherical aberration
    Light passing through a convex lens will be brought to different focus depending upon whether the light passes through near the center of the lens or closer to the periphery. Lens designers strive to correct this kind of zonal aberration to bring peripheral and near-central rays to a common focus.

  • Spot Metering
    Autoexposure is based on a meter reading of a small circle in the center of the viewfinder.

  • sRGB
    A calibrated RGB colour space, proposed as a Web standard.

  • Standard resolution
    Standard resolution is 640 x 480 pixels (H x V) and originates with the VGA standard first defined for the IBM PC. SVGA is the next step up in terms of resolution and covers 800 x 600. XGA define the 1024 x 768 resolution, while UXGA is used for 1280x1024 and 1600x1200. The higher the resolution the finer the image detail that can be seen.

  • stripping
    The traditional process of assembling colour separations and typeset text by hand prior to making printing press plates.

  • Subsampling
    Using an algorithm to derive a lower-resolution image from a higher-resolution image.

  • Subtractive colour
    "Combining cyan, magenta and yellow inks (or other colourants ) to create black

  • subtractive primaries
    The ink colours cyan, magenta, and yellow that add together to make black.